Recent advances in computer technology (i.e., the dramatic increase in speed and memory) and assistive technology software (i.e., existing On- screen keyboard systems) provide the foundation for an innovative approach t assisted typing. In the proposed effort, this new approach will be exploited and tested. "Dynamic Keyboards" are hypothesized to increase typing speed and accuracy in physically, mentally, and learning disabled users because they dynamically adapt an on-screen keyboard to the current typing context. Using "letter prediction", Dynamic Keyboards modify a displayed keyboard so that only those keys that are highly probable in that context are displayed or highlighted. Hypothesized sources of performance enhancement are due to 1) reduced visual scanning time, 2) less complex displays, 3) reduced probability of selecting an incorrect key, and 4) decreased key selection time for persons using scanning keyboards. In the proposed work, different approaches to Dynamic Keyboards will be identified, created, and evaluated in a user test involving the target user population. Subjective evaluations will be solicited and objective measures of typing performance under different experimental conditions will be collected and analyzed to demonstrate feasibility and potential. PROPOSED COMMERCIAL APPLICATIONS: If the proposed research demonstrates benefits of Dynamic Keyboards for improving typing speed and accuracy for persons who have difficulty using standard keyboards,the resulting software will be incorporated in an existing product and marketed to end users and organizations that provide services for the end users.